BOSTON - Many physicians in Massachusetts are ordering unnecessary and costly tests, procedures, referrals and prescriptions out of fear of lawsuits, a new survey reports.

Nearly 900 doctors in eight specialties, including family medicine, gynecology and anesthesiology, responded to the first-of-its-kind survey by the Waltham-based Massachusetts Medical Society.

The practice of so-called "defensive medicine" drives up the cost of health care in the Bay State by $1.4 billion, including unnecessary hospital admissions and tests, the study said. Admissions that are not needed cost $1.1 billion of that amount, the study said.

Dr. Stephen A. Metz of Springfield, a specialist in urogynecology, said he was surprised by the number of physicians involved in defensive medicine. He said he doesn't fault them for attempting to avoid lawsuits, especially when it is a close call about whether a test is needed.

A total of 83 percent of physicians who responded said they practice defensive medicine. An average 18 to 28 percent of tests, procedures, referrals and consultations and 13 percent of hospitalizations were ordered out of fear of being sued, the survey said.

Metz said the survey shows the need for overhauling medical malpractice laws in Massachusetts. He said the current tort system is a terrible way to provide justice and equity.

"Because there is a cone of silence imposed on everybody, there's no way you can look at the care to say what went wrong and how we can fix it," said Metz, president of the Hampden District Medical Society. "No one can talk."

A representative of the Massachusetts Academy of Trial Attorneys in Burlington said no one was available for comment. A spokesman for Health Care for All, an advocacy group in Boston, declined comment.

The medical society said it was the first study of its kind to specifically quantify defensive practices among a number of specialties and across a wide spectrum of doctors.

Thirty-eight percent of doctors surveyed said they reduced the number of high-risk services or procedures they performed and 28 percent reported reducing the number of high-risk patients they served.

Dr. Alan C. Woodward, an emergency physician and vice chairman of the medical society's professional liability committee, said the effects of defensive medicine are widespread. Woodward said the safety of patients could be at risk. If patients are exposed to unnecessary imaging tests, for example, they could have radiation exposure and possible severe allergic reactions to contrast dye, Woodward said.

The medical society said the skyrocketing cost of liability insurance is making it difficult to recruit and retain physicians especially those in high-risk specialties. Between 1992 and 2005, liability premiums for physicians rose by 132 percent, the medical society said.

The medical society is supporting several reform bills on Beacon Hill, including one requiring 182 days notice before filing a malpractice lawsuit. That would provide time for doctors and patients to negotiate a fair settlement prior to a lawsuit, the society said.

Another bill seeks to free doctors from legal liability if they apologize to patients and admit they made mistakes. Under the bill, such an apology or statement of regret couldn't be used as evidence against a doctor in a malpractice lawsuit.